Comodo Firewall

Comodo Firewall is your first layer of defense against viruses, malware, worms, Trojans, hackers, and all Internet threats. In order to prevent threats from occurring, rather than just detecting them when it's already too late, Comodo's Firewall utilizes unique Default Deny Protection. When a file or application knocks on your PC's door, Comodo Firewall is able to access a safe list of over 15 million files and applications that are known to be PC-friendly.